During the past 20 years, the continued evolution of computer processors, data-storage devices and subsystems, and networking, together with the emergence of the World Wide Web and broad consumer acceptance of the Internet, have created a vast new Internet-based retailing infrastructure that represents a significant portion of current retail transactions for products and services. In certain retail sectors, including books and recorded music, Internet-based retail transactions now rival or have surpassed traditional retailing media, including physical retail establishments and catalog-based mail-order and telephone transactions. It is expected that Internet-based retailing will continue to grow and assume increasingly greater shares of the total retail-transaction volumes on a worldwide basis.
As Internet-based retailing of products and services has evolved and increased in market share, a variety of new support industries have grown up around Internet-based retailing, including cloud computing, website-development services, Internet-transaction services, automated testing and optimization services, and web-analytics services. Automated testing and optimization services provide tools and infrastructure to allow owners and managers of websites to carry out experiments in which websites are systematically altered in order to determine salient features and characteristics of websites and modify the salient features and characteristics to improve website performance. Traditionally, automated testing systems have focused on conducting experiments which produce binomial results, such as whether a particular user ends up purchasing an item from the website or not during a user's session. While many different types of tests can be cast into the realm of binomial-result analysis, those who perform testing, optimization, and/or analysis, as well as those for whom testing, optimization, and/or analysis is performed, continue to seek more flexible and more broadly based testing, optimization, and/or analysis methods and systems in order to create and perform tests directed to understanding additional features, characteristics, and subtleties of website design and operation.